Why Can't Dogs Eat Chocolate?

By Josie F. Turner, Journalist specialized in Animal Welfare. Updated: September 18, 2017
Why Can't Dogs Eat Chocolate?

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We all have heard that dogs cannot eat chocolate, but have you wondered why?

There are many foods that we humans eat on a daily basis but that aren't at all recommended for our pets. This is because we are simply different species, and our organisms and physiology work in a different way.

If your pet has eaten chocolate by accident, or you have given it to them, or you simply have doubts about the best diet for dogs, stay with us at AnimalWised. Keep reading to learn why can't dogs eat chocolate - and watch carefully what your pet eats in the future!

You may also be interested in: Food You Can't Feed to Ferrets

The digestive system of dogs

In the digestive system of human beings - Homo sapiens - we can find specific enzymes that are used to metabolize and synthesize particular foods. These enzymes are a kind of proteins called Cytochrome P450, although they are usually called CYPs.

Cacao - like kola nut or tea leaves - contains an alkaloid called theobromine, quite similar to caffeine. This substance is metabolized by particular enzymes of the CYP family, which dogs do not have.

Since dogs do not have the necessary CYP enzymes to metabolize caffeine or theobromine fast enough, they can't properly digest them. Both these substances are found in chocolate; in big doses, chocolate is so toxic for dogs that it can gravely poison them and even kill them.

Due to their slow metabolism, 50 grams (less than 2 ounces) of milk chocolate are enough to kill a small dog. Dark chocolate is richer in theobromine, so it is even more dangerous.

Why Can't Dogs Eat Chocolate? - The digestive system of dogs

Consequences of eating chocolate

As a consequence of that lack of enzymes, it will take between one and two days for a dog to digest a piece of chocolate. During that process, if a dog has eaten a small piece, we will notice vomiting, diarrhea, hyperactivity, trembling and convulsions. In graver cases, there can even be a respiratory or cardiac failure.

If you suspect that your dog has eaten chocolate, take them to your vet so that they can perform a stomach washing.

By the way, many other animals do not have the right CYP enzymes and cannot metabolize chocolate. Cacao is also poisonous for cats, although they tend to ignore chocolate, unlike dogs. Bears also cannot eat chocolate.

Even humans can be poisoned by eating chocolate, although the dose required would be very, very high. Theobromine, like caffeine, stimulates the heart and can cause insomnia, anxiety, withdrawal aches and tremors. However, it's much lighter and doesn't make that much of an impact. Theobromine relaxes the muscles, including the ones in the bronchial area; this alkaloid has also been used to treat asthma.

Discover some foods that are forbidden for dogs and more specifically, which fruits and vegetables are forbidden.

If you want to read similar articles to Why Can't Dogs Eat Chocolate?, we recommend you visit our Diet problems category.

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linda sloan
I have a small male Chitsu about 7 pounds he ate a leftover chocolate im scared bcus i know dogs arent suppose to eat chocolate! :(

Jane Bertin (AnimalWised editor)
Hi! Take a look at your dog and try to see if he shows any of the symptoms described in the article, such as diarrhea or vomiting.

If he does, it's best to take him to the vet, although a single leftover chocolate should not cause big problems. If he acts normally and his digestive system seems alright, there's probably no reason to worry. We hope this is useful!
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